lowest common denominator

1(usually North American Englishleast common denominator)(mathematics)the smallest number that the bottom numbers of a group of fractions can be divided into exactly

2(North American English alsoleast common denominator)(disapproving)something that is simple enough to seem interesting to, or to be understood by, the highest number of people in a particular group; the sort of people who are least intelligent or accept something that is of low qualityThe school syllabus seems aimed at the lowest common denominator.